Some flat panel display devices include cathodes and anodes that are respectively aligned on two substrates to provide the display of an image. One type of flat panel display devices is an electron emission device (hereafter referred to as an EED). The EED includes a cold cathode electron emission source on a cathode substrate. The cathode substrate is aligned with an anode substrate on which green, blue and red color phosphor layers have been provided. Emitted electron beams collide with the green, blue and red color phosphor layers to exhibit colors.
A phosphor layer in an EED is in general composed of nonconductive particles, and therefore, there is a high possibility that an electric charge can be accumulated on the surface of the phosphor layer in the emission process of the phosphor layer when the EED is working (or active).
In the conventional EED, it is difficult to get advantageous emission brightness properties because the accumulated electric charge hinders electronic beams from reaching the phosphor layer when the electronic beams are transmitted into the phosphor screen.
U.S. Pat. No. 6,180,029 describes a method of using a phosphor that is spherical, small, and crystalline and has an even particle to improve emission brightness. Another U.S. Pat. No. 6,344,233, describes how to improve the resolution by preventing a phosphor from being contaminated with a phosphor layer made by using a slurry. The entire content in each of the above-cited patents is incorporated herein by reference. However, these methods and/or approaches are far from providing satisfactory results, and more research is still being undertaken to enhance emission brightness.